How Manufacturers Select Precision Ground Materials for Different Component Requirements
October 29, 2026
A CNC machine is only as consistent as what you feed it. You can dial in offsets, tune feeds, and check every first article, but if the bar stock varies from one piece to the next, the variation follows it into the finished part. That’s the problem precision ground bars are built to solve.
We’re Precision Ground Metals, Inc. in Palos Hills, IL. We’ve spent more than 30 years in the steel industry and grinding, and precision machining and CNC operations are among the industries we serve. The useful question isn’t just whether a bar is ground. It’s which ground bar product and which material fit the job on your machine. Here’s how we think about that match.
Matching the Ground Bar to the CNC Job
Every CNC job starts with two choices: the type of ground bar and the material it’s made from. Getting both right means fewer surprises once the program runs.
What does a precision ground bar give you to work with?
It gives you a known starting point. Each material with a listed ground tolerance has its own window. Stainless precision ground bars, for example, are held to h6, h7, and h8, while alloy steel and carbon steel precision ground bars are ground to ±0.0005″ or better.
For a CNC job, that number matters before the first chip is cut. When stock starts close to size and stays consistent bar to bar, there’s less material standing between the bar and the finished dimension, and fewer surprises when the next bar loads. Our Precision Ground Bars are made to exact tolerances for Swiss machines and high precision applications for exactly that reason.
Which ground bar product fits your job?
“Ground bar” covers more than one product, and each one leans toward a different need.
Precision Ground Bars are the starting point when dimensional accuracy is the main concern. Ground & Polished Bars add a smooth, uniform finish. Turned, Ground & Polished (TGP) Bars improve both dimensional accuracy and surface quality.
Some products are tied to a specific end use. Bearing Shaft Quality Bars are made for high wear resistance in linear motion applications. Pump Shaft Quality Bars are made for corrosion resistance in demanding environments. And Accuracy Stock is precision grade material ready to use across a range of industries.
If you’re not sure which one your print points to, tell us what the part does.
Which materials show up most in precision machining work?
Several of our materials are directly tied to CNC and precision machining applications.
Stainless steel precision ground bars are used in CNC precision machining, along with shafts and bearings, linear motion components, medical instruments, and aerospace and defense work. Our stainless grades run from 303 and 316/316L to 440C and 2507 Super Duplex.
Alloy steel serves spindles, bushings, bearings, and aerospace and automotive shafts and gears, with grades including 4140, 4340, and 52100. Carbon steel precision ground bars in 1018 and 1045 go into precision shafts, guide rails, linear motion components, and die and mold components.
On the non ferrous side, brass is used in precision machining, and C360 free machining brass is used for precision components and valves. Copper is used in high precision machining. C14500 tellurium copper offers high machinability, and C14700 sulfur copper is used for precision machined electrical parts.
How does a stainless ground bar reach its finish?
Our stainless precision ground bars follow a set sequence: cold drawing, grinding, polishing, and then inspection. They’re centerless ground to a surface finish of Ra ≤ 0.2 to 0.8 µm.
That sequence matters for CNC work because inspection comes last. The bar is checked after grinding and polishing, so what reaches your shop reflects the finished condition, not an intermediate one.
What can arrive with the bar?
A ground bar can still slow you down if it shows up the wrong length or with rough ends. We can straighten bars to strict straightness tolerances, finish the ends with a smooth, burr free chamfer, and cut lengths to your specifications. Material ships in protective packaging and is delivered to your location.
For parts headed into defense or regulated programs, we supply material with DFARS, REACH, and RoHS compliance, and most of our materials are domestically made.
What should you send when you request a quote?
Start with your contact details and material of interest. Then use the special request notes for the details that matter to your machine: grade, ground bar product type, tolerance, finish, lengths, any straightening, chamfering, or cutting, and any compliance requirements. The more we know about the CNC job, the closer our first answer will be.
Let’s Set Up Your Next Run Right
If you’ve got a CNC job where the stock has to be right before the program even starts, send us the print. We’ll help you choose the ground bar product and material that fit it. Call (708) 400-7217, email sales@precisiongroundmetals.com, or use our Request A Quote form.
FAQs
Which ground bar product should I choose for a CNC job?
Precision Ground Bars suit jobs where dimensional accuracy is the main concern. Ground & Polished Bars add a smooth, uniform finish, and Turned, Ground & Polished (TGP) Bars improve both dimensional accuracy and surface quality.
Do you offer bars made for specific end uses?
Yes. Bearing Shaft Quality Bars are made for high wear resistance in linear motion applications, and Pump Shaft Quality Bars are made for corrosion resistance in demanding environments.
Which materials are used for CNC and precision machining?
Stainless steel precision ground bars are used in CNC precision machining. Brass is used in precision machining, with C360 used for precision components. Copper is used in high precision machining.
Can you cut and chamfer bars before they ship?
Yes. We offer custom cut lengths, chamfered bar ends, straightening, protective packaging, and delivery to your location.
